feat: add task display mode option to start of chat streams (#2479)

srtaalej · mwbrooks · zimeg · web-flow · commit f2ac218d56f2 · 2026-01-27T11:42:01.000-05:00
Co-authored-by: Michael Brooks &lt;mbrooks@slack-corp.com&gt;
Co-authored-by: Eden Zimbelman &lt;eden.zimbelman@salesforce.com&gt;
diff --git a/packages/web-api/src/types/request/chat.ts b/packages/web-api/src/types/request/chat.ts
@@ -255,6 +255,11 @@ export interface ChatStartStreamArguments extends TokenOverridable, Channel, Par
    * This is required when starting a streaming conversation outside of a DM.
    */
   recipient_user_id?: string;
+  /**
+   *  @description Specifies how tasks are displayed in the message. A "timeline" displays individual tasks
+   * interleaved with text and "plan" displays all tasks together.
+   */
+  task_display_mode?: string;
 }
 
 export type ChatStopStreamArguments = TokenOverridable &
diff --git a/packages/web-api/test/types/methods/chat.test-d.ts b/packages/web-api/test/types/methods/chat.test-d.ts
@@ -833,6 +833,33 @@ expectAssignable<Parameters<typeof web.chat.startStream>>([
   },
 ]);
 
+expectAssignable<Parameters<typeof web.chat.startStream>>([
+  {
+    channel: 'C1234',
+    thread_ts: '1234.56',
+    chunks: [
+      {
+        type: 'markdown_text',
+        text: 'Hello world',
+      },
+      {
+        type: 'plan_update',
+        title: 'Hello world',
+      },
+      {
+        type: 'task_update',
+        id: 'task-1',
+        title: 'Processing request',
+        status: 'in_progress',
+        details: 'Working on it...',
+      },
+    ],
+    recipient_team_id: 'T1234',
+    recipient_user_id: 'U1234',
+    task_display_mode: 'timeline', // Expect to be supported
+  },
+]);
+
 // chat.stopStream
 // -- sad path
 expectError(web.chat.stopStream()); // lacking argument
